THROMBOEMBOLISM remains a significant cause of morbidity and mortality. When efforts to prevent the intravascular formation of thrombus have failed, the problem remains of preventing the passage of emboli from the peripheral veins to the right side of the heart and lungs. Several operations on the inferior vena cava have been used to accomplish this without significantly reducing venous return or raising the distal venous pressure. These operations include stapling1, suture filters,2 plication with mattress sutures,3 plication with a suture threaded with beads,4 partial ligation,5 application of a self-releasing spring clip,6 a serrated clip,7 a smooth clip,8 and a clip, one arm of which is smooth, the other serrated.9 All were designed to protect the patient from lethal emboli without producing the complications of inferior vena cava ligation, eg, embolization of thrombus formed proximal to the ligation site, dependent edema, pain,